AppX & UWP Frequently Asked Questions

What is an .AppX?

The .AppX is the file format used to distribute and install apps on the Universal Windows Platform. The .AppX is an .ZIP-based container file.

What does an AppX package contains?

Each Windows Runtime app package contains the app’s payload files plus info needed to validate, deploy, manage, and update the app.

In a .appx package you will find:

  • App payload which are the Application files
  • XML configuration files which are:
    • App manifest which is the app manifest file (AppxManifest.xml)
    • App block map which is the app package’s block map file (AppxBlockMap.xml)
  • App signature

What is the installation type of an UWP app?

The UWP app is installed per-user. Users don't have any knowledge of what was installed for any other user.

Where the UWP apps get installed?

In UWP apps we have app isolation mechanism, which means they only impact the account of the user who installed them. The app binaries are stored on the drive (%ProgramFiles%\WindowsApps). Only the Operating System can write in that location. The application cannot write in that location, the application is running in sandbox.

What is a Centennial UWP package?

The Centennial UWP packages are Win32 apps converted to AppX. Are also called full trusted apps.

How to install an AppX package from other sources that you trust, outside the Windows Store?

A requirement is to have "Sideload apps" option enabled on your target machine from "Settings" -> "Update and security" -> "For developers".

There are two ways to sideload apps after Windows 10 Anniversary Update:

  • Full trust apps: double click the AppX file from Windows Explorer and follow the graphical installer
  • Untrusted apps:
    • import the security certificate used to sign the AppX into the system store
    • run Powershell cmdlet as admin
    • run following command pointing to the .AppX file on the target system:
Add-AppxPackage -Path "C:\Path\Your.Appx"

TipTo build a full trust .AppX package from Advanced Installer you must enable the option from the Capabilities Page.

Why do I receive the "External tool not found: MakePri.exe" error during the UwpAppX build?

For creating UwpAppX packages with Advanced Installer, the build machine must have the latest Windows SDK installed.

Why do I receive the "Error: SignerSign() failed. (-2147024885/0x8007000b)" error during the UwpAppX build?

This error may occur if the ID field from the Package Information view does not match with the publisher subject information of the certificate used to sign the package.

Why do I receive the "You must include at least one Application in an UwpAppx build" error during the UwpAppX build?

For Advanced Installed:

When you create your UwpAppX build, Advanced Installer checks your AIP project for the shortcut(s) to your application(s). If you don't have any shortcut(s), it won't know what application(s) you want to add to your UwpAppX build, and you will get this error. There are two solutions:

  1. Add your application(s) manually to the Application Details page
  2. Create the shortcut(s) for your application(s); they will be added automatically to your UwpAppX build

For Desktop Bridge Setup Convertor:

Applications are created automatically from your shortcuts when the UwpAppX build generates. If no shortcuts are found/captured by our converter, you get an error. Make sure you do not untick all the shortcuts from the dialog presenting you the summary of the package contents.

If your installer does not create shortcuts, you can create them manually after the installation has finished, while converting your application, before you press ENTER and let the converter continue its last step of the conversion/monitoring process.

I have just converted a classic desktop application to an AppX package, why do I receive the “Failed due to unknown reasons” when I try to install it?

This error may occur if you have not included in your Advanced Installer Project all the images in Visual Assets and Package Information for all the required resolutions and tile sizes.

Matteo Pagani's blog post offers a solution for the same issue if you used Microsoft's Desktop App Converter for the conversion.

Can I configure the default app launched at the end of the deployment of an AppX bundle?

When you install a multi-app package from the Windows Store, there is no [ Launch ] button. Instead, you are directed to the app list to choose what app you want to start, meaning you cannot have a default app for an AppX bundle.